This invention relates to radiographic cameras. More particularly, this invention relates to a jacket for radiographic cameras, a connection between a radiation source shield to a housing of a radiographic camera, and a connector assembly for a radiographic camera.
An X-ray machine can be used to make photographic images that indicate the internal composition of objects. One well known use is the detection of broken or fractured bones. A typical X-ray machine is inadequate for some tasks because it is unable to make photographic images of the interior structure of metals. Since a typical X-ray machine is large and requires a power source, it cannot be used in remote locations without significant expense.
Radiographic cameras are used to make images similar to X-ray images, but are used with greater flexibility. A radiographic camera can record images of the interior structure of metals that cannot be imaged with an X-ray machine. In addition, these cameras are portable and operate without an external power source. Therefore they are useful in taking images of objects in their natural environment. Radiographic cameras are used extensively in the oil industry, for example, to check for flaws in metal pipelines that could otherwise cause oil spills.
A typical radiographic camera and source are described in U.S. Pat. Nos. 5,065,033 and 4,827,493, respectively. Each of these patents is assigned to the same assignee as the present invention, and each is hereby incorporated by reference in their entirety. As shown in FIG. 1 of U.S. Pat. No. 5,065,033, an S-shaped tubing extends from a back end of the camera to a front end. The tubing is surrounded by a radiation shield and encloses a radiographic source at the end of a source cable. Typically, the S-shaped shaped tube attaches the radiation shield to a housing at the back and front ends of the camera. A typical radiographic source includes stacked iridium-192 wafers that are contained inside a welded capsule. Since the radiographic source emits radiation in a line, when the source is in a stored position (as in FIG. 1), only minimal radiation is reflected toward the front end, by which time any radiation that remains is significantly decreased.
A lock assembly is provided over an opening at the back end of the camera, and a threaded nut blocks an opening at the front end. Control cables are attached to the back end, and a guide cable is screwed to the front end. The lock assembly in the back prevents the radiation source from being pushed out of the front end without first using a key to unlock the camera, and then connecting a control cable. At the front end of a typical camera, a technician removes the threaded nut, and attaches a guide cable with a threaded end over the threaded mount on the housing. When the control cables and guide cable are positioned, the technician operates a hand crank to move a wire in the control cable, which pushes the source out of the camera housing, and to the end of the guide cable. The end of the guide cable is then positioned on one side of an object that is to be imaged, and photographic cassettes are placed on the other side. The technician sets the exposure time. When finished, the technician reverses the direction of the crank to retract the source.
U.S. Pat. No. 5,418,379, assigned to the same assignee as the present invention and hereby incorporated by reference in its entirety, discloses a connector assembly. As shown in FIG. 3, a plug assembly blocks the front opening when in a stored position. The plug cannot be completely removed from the connector assembly until a shield is first moved to block the opening by operating a manually actuable slide. An interlock mechanism is also disclosed that is provided between the lock assembly at the back of the camera and the connector assembly so that the lock assembly cannot be actuated to receive the control cables until the guide cable is coupled to the front end. Thus, either the guide cable or plug assembly must be on the connector assembly in order for the lock assembly to be accessed.
According to the present invention, a radiographic camera is disclosed having certain improvements. In one illustrative embodiment of the invention, a jacket for the radiographic camera includes a front end, a back end opposite the front end and a handle positioned between the ends, where the handle includes a reinforcement structure. The reinforcement structure may include a wire and an additional protective element, such as a tube. In an illustrative embodiment, the jacket has an opening for receiving a radiographic camera that extends through the front end of the jacket to the back end of the jacket. The wire surrounds the opening at the front end, extends through the handle and surrounds the opening at the back end of the camera. Ferrules may be provided to secure the ends of the wire in the handle. The jacket may be made of molded polyurethane and the wire and the tubing may be stainless steel. Additionally, the jacket may be removably secured to the radiographic camera so that it may be removed from the camera, if desired.
In another illustrative embodiment of the invention, a radiographic camera includes a housing having a source surrounded by a shield assembly, where the shield has first and second shield ends and an endplate having a first surface secured to the first shield end. A bracket may be provided on the first surface of the endplate and secured to the first shield end. For example, a pin may be used to removably secure the shield end to the bracket. The second shield end may also be secured to a second bracket on a second endplate with a second pin. The pin may be solid titanium, the shield may be depleted uranium, and the endplate and bracket may be stainless steel. A spacer made of copper may be provided between each shield end and bracket. Additionally, a port outlet may be formed through the endplates and brackets to receive a conduit for the source.
In another illustrative embodiment of the invention, a connector assembly is provided for a radiographic camera which has a housing containing a source in a pathway surrounded by a radiation shield. A first end of the housing includes a first opening in communication with the pathway. A shield protector is adapted to block and unblock the first opening. The shield protector is provided between the first endplate and a front plate. The front plate includes a second opening aligned with the first opening and adapted to receive a cable guide fitting that allows the shield protector to unblock the first opening and expose the source.
The shield protector may be a rotor rotatably attached an interior surface of the front plate between the front plate and the first endplate. The rotor may have a first rotor hole for locating a port shield to be aligned with the first opening rotor. The rotor may also have a second rotor hole adapted to be aligned with the first opening when the rotor is rotated.
A slider may be provided adjacent the rotor. The slider prevents the rotor from rotating. The second opening may be adapted to receive the guide cable fitting to move the slider to allow the rotor to rotate and expose the first opening through the second rotor hole.
A knob may be provided rotatably attached to an exterior surface of the front plate and positioned to cover and uncover the second opening. The knob is rotatable to expose the second opening such that the guide cable fitting may be inserted within the second opening to move the slider. Thus, the knob may further rotate to align the second rotor hole within the first opening and the second opening to expose the source.
In another illustrative embodiment of the invention, a connector assembly includes a connection element, a shield protector and a lock. The connection element is adapted to engage with a guide cable. The connection element has an opening aligned with a radiation source opening in the camera through which a radiation source can pass. The shield protector may be moved between blocking and unblocking positions. The blocking position has the shield protector blocking the radiation source opening. The unblocking position has the shield protector not blocking the radiation source opening. The lock is adapted to lock the shield protector in the blocking position and is adapted to unlock the shield protector upon activating a key that allows the shield protector to move to the unblocking position. The shield protector may include a rotor to block and unblock the radiation source opening. The lock may include a slider that is adapted to engage with a key to unlock the rotor from the blocking position. The connector assembly may also include a knob adapted to move the rotor to unblock the radiation source opening upon engagement of the slider with the key. The lock may also be adapted to engage with a guide cable fitting that acts as a key. The lock may include a slider that unlocks the shield protector from the blocking position when the guide cable fitting is secured to the opening in the connection element.
In another illustrative embodiment of the invention, a method of operating a radiation camera is provided. The method includes the step of unlocking a shield protector that blocks a radiation source opening of the camera. Further, steps include moving the shield protector to unblock the radiation source opening and moving a radiation source from within the camera through the radiation source opening. The step of unlocking the shield protector may include attaching a guide cable fitting to the camera. The step of unlocking the shield protector may include engaging the guide cable fitting with a slider. The step of moving the shield protector may include rotating a knob attached to the shield protector to align a hole on the shield protector with the radiation source opening.